Behavior: Jean Piaget: Mapping the Growing Mind

IT is late afternoon, but the four-year-old insists: "It can't be. I
haven't had my nap." Such is the mind of the child, by most indications
illogical and full of nonsense. Not so, says Jean Piaget, a grumpy,
mountain-climbing Swiss philosopher who is also one of the world's
foremost child psychologists. Few researchers have so meticulously or
provocatively mapped that terra incognita, the mental world of
children. For 50 years, Piaget, now 73, has been discovering through
deceptively simple experiments that children actually have surprisingly
intricate thinking skills that adults should learn to...